1. Field of the Invention
The present invention relates generally to the investment casting, and particularly to a process for preparing an investment casting mold composed of an inner mold core and an outer shell mold baked simultaneously at a single baking step.
2. Related Art Statement
A ceramic mold core used or assembled within a mold for an investment casting process should have a strength which is high enough to withstand the injection molding of a wax model and having a strength at high temperature which is sufficient for retaining its inegrity under a high temperature environment, during the sintering and/or casting steps. Prior art cores conventionally used for such purposes are molded from aggregates, such as those containing alumina, zirconia or fused silica. Then the thus molded cores are burned or sintered singly. However, such a process leads to a low producibility in production of cores and lowers the overall operation efficiency.
A further disadvantage of the conventional process is that the sintered core molds used therein are hard to demolish after use. They cannot be removed from the cast product by the application of physical vibration or impact. Thus, cumbersome and inefficient operations are required for the removal of such core molds, leading to increase in production cost.